Devices for transporting and weighing objects that pass the device in a serial manner are particularly known from letter processing. In letter distribution centers, the letters are supplied sequentially and in rapid succession to a scale in order to determine their weight there. The letters are usually transported on edge or upright and are subsequently supplied to a transport unit arranged on a weighing cell. The weight of this transport unit is coupled to the load receiver of a weighing cell so that the weight of the letter present in the transport unit can be detected and processed.
The weighing is preferably done in rapid succession, so that the letters are moved at high speed, whereby the residence time in the transport unit that is available for weighing technology to detect the weight becomes small. The mass and shape of the letter has detrimental effects on the settling process of the measurement signal from the weighing cell. Thus, deflection movements or air currents that unintentionally influence the measurement cell can act on the letter held in the transport unit. The type and size or mass of the transport unit seated on the weighing cell can also falsify the measurement result. A large and therefore inertial mass slows the settling process of the measurement signal. An imbalance in the moved part likewise leads to measuring errors. A large surface area leads to increased wind sensitivity.
A device for printing on a print substrate situated on its edge is described in DE 196 05 015 C1. The printing substrate is pressed by pressing elements against a guide plate so that it is positively held during transport and the printing process. The device is not suitable for weighing, and the guide plate is relatively large.
The present invention addresses the problem of weight measurement errors in devices that transport a series of objects and weigh the objects in rapid succession.